Since 1987, we have examined over 100 DNA bases and nucleosides that are modified with carcinogenic polycyclic aromatic hydrocarbons (PAH). More recently, we have expanded the research to include potentially carcinogenic steroid hormones (e.g., estrogens). The research has been expanded to include metastable-ion studied, low energy collisional activation (on triple quadrupoles), and post-source decompositions (PSD) on MALD1/time-of-flight instruments. The goal is to understand the ion chemistry associated with the fragmentation, to provide insight on the mechanism of PSD, and to evaluate the advantages and limitations of the various methods for inducing fragmentation in biomolecules.